    /**
     * @class Ext.draw.engine.Svg
     * Provides specific methods to draw with SVG.
     */
    Ext.define('Ext.draw.engine.Svg', {

        /* Begin Definitions */

        extend: 'Ext.draw.Surface',

        requires: ['Ext.draw.Draw', 'Ext.draw.Sprite', 'Ext.draw.Matrix', 'Ext.Element'],

        /* End Definitions */

        engine: 'Svg',

        trimRe: /^\s+|\s+$/g,
        spacesRe: /\s+/,
        xlink: "http:/" + "/www.w3.org/1999/xlink",

        translateAttrs: {
            radius: "r",
            radiusX: "rx",
            radiusY: "ry",
            path: "d",
            lineWidth: "stroke-width",
            fillOpacity: "fill-opacity",
            strokeOpacity: "stroke-opacity",
            strokeLinejoin: "stroke-linejoin"
        },

        parsers: {},

        minDefaults: {
            circle: {
                cx: 0,
                cy: 0,
                r: 0,
                fill: "none",
                stroke: null,
                "stroke-width": null,
                opacity: null,
                "fill-opacity": null,
                "stroke-opacity": null
            },
            ellipse: {
                cx: 0,
                cy: 0,
                rx: 0,
                ry: 0,
                fill: "none",
                stroke: null,
                "stroke-width": null,
                opacity: null,
                "fill-opacity": null,
                "stroke-opacity": null
            },
            rect: {
                x: 0,
                y: 0,
                width: 0,
                height: 0,
                rx: 0,
                ry: 0,
                fill: "none",
                stroke: null,
                "stroke-width": null,
                opacity: null,
                "fill-opacity": null,
                "stroke-opacity": null
            },
            text: {
                x: 0,
                y: 0,
                "text-anchor": "start",
                "font-family": null,
                "font-size": null,
                "font-weight": null,
                "font-style": null,
                fill: "#000",
                stroke: null,
                "stroke-width": null,
                opacity: null,
                "fill-opacity": null,
                "stroke-opacity": null
            },
            path: {
                d: "M0,0",
                fill: "none",
                stroke: null,
                "stroke-width": null,
                opacity: null,
                "fill-opacity": null,
                "stroke-opacity": null
            },
            image: {
                x: 0,
                y: 0,
                width: 0,
                height: 0,
                preserveAspectRatio: "none",
                opacity: null
            }
        },

        createSvgElement: function(type, attrs) {
            var el = this.domRef.createElementNS("http:/" + "/www.w3.org/2000/svg", type),
                key;
            if (attrs) {
                for (key in attrs) {
                    el.setAttribute(key, String(attrs[key]));
                }
            }
            return el;
        },

        createSpriteElement: function(sprite) {
            // Create svg element and append to the DOM.
            var el = this.createSvgElement(sprite.type);
            el.id = sprite.id;
            if (el.style) {
                el.style.webkitTapHighlightColor = "rgba(0,0,0,0)";
            }
            sprite.el = Ext.get(el);
            this.applyZIndex(sprite); //performs the insertion
            sprite.matrix = new Ext.draw.Matrix();
            sprite.bbox = {
                plain: 0,
                transform: 0
            };
            this.applyAttrs(sprite);
            this.applyTransformations(sprite);
            sprite.fireEvent("render", sprite);
            return el;
        },

        getBBoxText: function (sprite) {
            var bbox = {},
                bb, height, width, i, ln, el;

            if (sprite && sprite.el) {
                el = sprite.el.dom;
                try {
                    bbox = el.getBBox();
                    return bbox;
                } catch(e) {
                    // Firefox 3.0.x plays badly here
                }
                bbox = {x: bbox.x, y: Infinity, width: 0, height: 0};
                ln = el.getNumberOfChars();
                for (i = 0; i < ln; i++) {
                    bb = el.getExtentOfChar(i);
                    bbox.y = Math.min(bb.y, bbox.y);
                    height = bb.y + bb.height - bbox.y;
                    bbox.height = Math.max(bbox.height, height);
                    width = bb.x + bb.width - bbox.x;
                    bbox.width = Math.max(bbox.width, width);
                }
                return bbox;
            }
        },

        hide: function() {
            Ext.get(this.el).hide();
        },

        show: function() {
            Ext.get(this.el).show();
        },

        hidePrim: function(sprite) {
            this.addCls(sprite, Ext.baseCSSPrefix + 'hide-visibility');
        },

        showPrim: function(sprite) {
            this.removeCls(sprite, Ext.baseCSSPrefix + 'hide-visibility');
        },

        getDefs: function() {
            return this._defs || (this._defs = this.createSvgElement("defs"));
        },

        transform: function(sprite, matrixOnly) {
            var me = this,
                matrix = new Ext.draw.Matrix(),
                transforms = sprite.transformations,
                transformsLength = transforms.length,
                i = 0,
                transform, type;

            for (; i < transformsLength; i++) {
                transform = transforms[i];
                type = transform.type;
                if (type == "translate") {
                    matrix.translate(transform.x, transform.y);
                }
                else if (type == "rotate") {
                    matrix.rotate(transform.degrees, transform.x, transform.y);
                }
                else if (type == "scale") {
                    matrix.scale(transform.x, transform.y, transform.centerX, transform.centerY);
                }
            }
            sprite.matrix = matrix;
            if (!matrixOnly) {
                sprite.el.set({transform: matrix.toSvg()});
            }
        },

        setSize: function(width, height) {
            var me = this,
                el = me.el;

            width = +width || me.width;
            height = +height || me.height;
            me.width = width;
            me.height = height;

            el.setSize(width, height);
            el.set({
                width: width,
                height: height
            });
            me.callParent([width, height]);
        },

        /**
         * Get the region for the surface's canvas area
         * @returns {Ext.util.Region}
         */
        getRegion: function() {
            // Mozilla requires using the background rect because the svg element returns an
            // incorrect region. Webkit gives no region for the rect and must use the svg element.
            var svgXY = this.el.getXY(),
                rectXY = this.bgRect.getXY(),
                max = Math.max,
                x = max(svgXY[0], rectXY[0]),
                y = max(svgXY[1], rectXY[1]);
            return {
                left: x,
                top: y,
                right: x + this.width,
                bottom: y + this.height
            };
        },

        onRemove: function(sprite) {
            if (sprite.el) {
                sprite.el.destroy();
                delete sprite.el;
            }
            this.callParent(arguments);
        },

        setViewBox: function(x, y, width, height) {
            if (isFinite(x) && isFinite(y) && isFinite(width) && isFinite(height)) {
                this.callParent(arguments);
                this.el.dom.setAttribute("viewBox", [x, y, width, height].join(" "));
            }
        },

        render: function (container) {
            var me = this,
                width,
                height,
                el,
                defs,
                bgRect,
                webkitRect;
            if (!me.el) {
                width = me.width || 0;
                height = me.height || 0;
                el = me.createSvgElement('svg', {
                    xmlns: "http:/" + "/www.w3.org/2000/svg",
                    version: 1.1,
                    width: width,
                    height: height
                });
                defs = me.getDefs();

                // Create a rect that is always the same size as the svg root; this serves 2 purposes:
                // (1) It allows mouse events to be fired over empty areas in Webkit, and (2) we can
                // use it rather than the svg element for retrieving the correct client rect of the
                // surface in Mozilla (see https://bugzilla.mozilla.org/show_bug.cgi?id=530985)
                bgRect = me.createSvgElement("rect", {
                    width: "100%",
                    height: "100%",
                    fill: "#000",
                    stroke: "none",
                    opacity: 0
                });

                if (Ext.isSafari3) {
                    // Rect that we will show/hide to fix old WebKit bug with rendering issues.
                    webkitRect = me.createSvgElement("rect", {
                        x: -10,
                        y: -10,
                        width: "110%",
                        height: "110%",
                        fill: "none",
                        stroke: "#000"
                    });
                }
                el.appendChild(defs);
                if (Ext.isSafari3) {
                    el.appendChild(webkitRect);
                }
                el.appendChild(bgRect);
                container.appendChild(el);
                me.el = Ext.get(el);
                me.bgRect = Ext.get(bgRect);
                if (Ext.isSafari3) {
                    me.webkitRect = Ext.get(webkitRect);
                    me.webkitRect.hide();
                }
                me.el.on({
                    scope: me,
                    mouseup: me.onMouseUp,
                    mousedown: me.onMouseDown,
                    mouseover: me.onMouseOver,
                    mouseout: me.onMouseOut,
                    mousemove: me.onMouseMove,
                    mouseenter: me.onMouseEnter,
                    mouseleave: me.onMouseLeave,
                    click: me.onClick,
                    dblclick: me.onDblClick
                });
            }
            me.renderAll();
        },

        // private
        onMouseEnter: function(e) {
            if (this.el.parent().getRegion().contains(e.getPoint())) {
                this.fireEvent('mouseenter', e);
            }
        },

        // private
        onMouseLeave: function(e) {
            if (!this.el.parent().getRegion().contains(e.getPoint())) {
                this.fireEvent('mouseleave', e);
            }
        },
        // @private - Normalize a delegated single event from the main container to each sprite and sprite group
        processEvent: function(name, e) {
            var target = e.getTarget(),
                surface = this.surface,
                sprite;

            this.fireEvent(name, e);
            // We wrap text types in a tspan, sprite is the parent.
            if (target.nodeName == "tspan" && target.parentNode) {
                target = target.parentNode;
            }
            sprite = this.items.get(target.id);
            if (sprite) {
                sprite.fireEvent(name, sprite, e);
            }
        },

        /* @private - Wrap SVG text inside a tspan to allow for line wrapping.  In addition this normallizes
         * the baseline for text the vertical middle of the text to be the same as VML.
         */
        tuneText: function (sprite, attrs) {
            var el = sprite.el.dom,
                tspans = [],
                height, tspan, text, i, ln, texts, factor, x;

            if (attrs.hasOwnProperty("text")) {
                //only create new tspans for text lines if the text has been
                //updated or if it's the first time we're setting the text
                //into the sprite.

                //get the actual rendered text.
                text = sprite.tspans && Ext.Array.map(sprite.tspans, function(t) { return t.textContent; }).join('');

                if (!sprite.tspans || attrs.text != text) {
                    tspans = this.setText(sprite, attrs.text);
                    sprite.tspans = tspans;
                //for all other cases reuse the tspans previously created.
                } else {
                    tspans = sprite.tspans || [];
                }
            }
            // Normalize baseline via a DY shift of first tspan. Shift other rows by height * line height (1.2)
            if (tspans.length) {
                height = this.getBBoxText(sprite).height;
                x = sprite.el.dom.getAttribute("x");
                for (i = 0, ln = tspans.length; i < ln; i++) {
                    // The text baseline for FireFox 3.0 and 3.5 is different than other SVG implementations
                    // so we are going to normalize that here
                    factor = (Ext.isFF3_0 || Ext.isFF3_5) ? 2 : 4;
                    tspans[i].setAttribute("x", x);
                    tspans[i].setAttribute("dy", i ? height * 1.2 : height / factor);
                }
                sprite.dirty = true;
            }
        },

        setText: function(sprite, textString) {
             var me = this,
                 el = sprite.el.dom,
                 tspans = [],
                 height, tspan, text, i, ln, texts;

            while (el.firstChild) {
                el.removeChild(el.firstChild);
            }
            // Wrap each row into tspan to emulate rows
            texts = String(textString).split("\n");
            for (i = 0, ln = texts.length; i < ln; i++) {
                text = texts[i];
                if (text) {
                    tspan = me.createSvgElement("tspan");
                    tspan.appendChild(document.createTextNode(Ext.htmlDecode(text)));
                    el.appendChild(tspan);
                    tspans[i] = tspan;
                }
            }
            return tspans;
        },

        renderAll: function() {
            this.items.each(this.renderItem, this);
        },

        renderItem: function (sprite) {
            if (!this.el) {
                return;
            }
            if (!sprite.el) {
                this.createSpriteElement(sprite);
            }
            if (sprite.zIndexDirty) {
                this.applyZIndex(sprite);
            }
            if (sprite.dirty) {
                this.applyAttrs(sprite);
                if (sprite.dirtyTransform) {
                    this.applyTransformations(sprite);
                }
            }
        },

        redraw: function(sprite) {
            sprite.dirty = sprite.zIndexDirty = true;
            this.renderItem(sprite);
        },

        applyAttrs: function (sprite) {
            var me = this,
                el = sprite.el,
                group = sprite.group,
                sattr = sprite.attr,
                parsers = me.parsers,
                //Safari does not handle linear gradients correctly in quirksmode
                //ref: https://bugs.webkit.org/show_bug.cgi?id=41952
                //ref: EXTJSIV-1472
                gradientsMap = me.gradientsMap || {},
                safariFix = Ext.isSafari && !Ext.isStrict,
                groups, i, ln, attrs, font, key, style, name, rect;

            if (group) {
                groups = [].concat(group);
                ln = groups.length;
                for (i = 0; i < ln; i++) {
                    group = groups[i];
                    me.getGroup(group).add(sprite);
                }
                delete sprite.group;
            }
            attrs = me.scrubAttrs(sprite) || {};

            // if (sprite.dirtyPath) {
                sprite.bbox.plain = 0;
                sprite.bbox.transform = 0;
                if (sprite.type == "circle" || sprite.type == "ellipse") {
                    attrs.cx = attrs.cx || attrs.x;
                    attrs.cy = attrs.cy || attrs.y;
                }
                else if (sprite.type == "rect") {
                    attrs.rx = attrs.ry = attrs.r;
                }
                else if (sprite.type == "path" && attrs.d) {
                    attrs.d = Ext.draw.Draw.pathToString(Ext.draw.Draw.pathToAbsolute(attrs.d));
                }
                sprite.dirtyPath = false;
            // }
            // else {
            //     delete attrs.d;
            // }

            if (attrs['clip-rect']) {
                me.setClip(sprite, attrs);
                delete attrs['clip-rect'];
            }
            if (sprite.type == 'text' && attrs.font && sprite.dirtyFont) {
                el.set({ style: "font: " + attrs.font});
            }
            if (sprite.type == "image") {
                el.dom.setAttributeNS(me.xlink, "href", attrs.src);
            }
            Ext.applyIf(attrs, me.minDefaults[sprite.type]);

            if (sprite.dirtyHidden) {
                (sattr.hidden) ? me.hidePrim(sprite) : me.showPrim(sprite);
                sprite.dirtyHidden = false;
            }
            for (key in attrs) {
                if (attrs.hasOwnProperty(key) && attrs[key] != null) {
                    //Safari does not handle linear gradients correctly in quirksmode
                    //ref: https://bugs.webkit.org/show_bug.cgi?id=41952
                    //ref: EXTJSIV-1472
                    //if we're Safari in QuirksMode and we're applying some color attribute and the value of that
                    //attribute is a reference to a gradient then assign a plain color to that value instead of the gradient.
                    if (safariFix && ('color|stroke|fill'.indexOf(key) > -1) && (attrs[key] in gradientsMap)) {
                        attrs[key] = gradientsMap[attrs[key]];
                    }
                    //hidden is not a proper SVG attribute.
                    if (key == 'hidden' && sprite.type == 'text') {
                        continue;
                    }
                    if (key in parsers) {
                        el.dom.setAttribute(key, parsers[key](attrs[key], sprite, me));
                    } else {
                        el.dom.setAttribute(key, attrs[key]);
                    }
                }
            }

            if (sprite.type == 'text') {
                me.tuneText(sprite, attrs);
            }
            sprite.dirtyFont = false;

            //set styles
            style = sattr.style;
            if (style) {
                el.setStyle(style);
            }

            sprite.dirty = false;

            if (Ext.isSafari3) {
                // Refreshing the view to fix bug EXTJSIV-1: rendering issue in old Safari 3
                me.webkitRect.show();
                setTimeout(function () {
                    me.webkitRect.hide();
                });
            }
        },

        setClip: function(sprite, params) {
            var me = this,
                rect = params["clip-rect"],
                clipEl, clipPath;
            if (rect) {
                if (sprite.clip) {
                    sprite.clip.parentNode.parentNode.removeChild(sprite.clip.parentNode);
                }
                clipEl = me.createSvgElement('clipPath');
                clipPath = me.createSvgElement('rect');
                clipEl.id = Ext.id(null, 'ext-clip-');
                clipPath.setAttribute("x", rect.x);
                clipPath.setAttribute("y", rect.y);
                clipPath.setAttribute("width", rect.width);
                clipPath.setAttribute("height", rect.height);
                clipEl.appendChild(clipPath);
                me.getDefs().appendChild(clipEl);
                sprite.el.dom.setAttribute("clip-path", "url(#" + clipEl.id + ")");
                sprite.clip = clipPath;
            }
            // if (!attrs[key]) {
            //     var clip = Ext.getDoc().dom.getElementById(sprite.el.getAttribute("clip-path").replace(/(^url\(#|\)$)/g, ""));
            //     clip && clip.parentNode.removeChild(clip);
            //     sprite.el.setAttribute("clip-path", "");
            //     delete attrss.clip;
            // }
        },

        /**
         * Insert or move a given sprite's element to the correct place in the DOM list for its zIndex
         * @param {Ext.draw.Sprite} sprite
         */
        applyZIndex: function(sprite) {
            var me = this,
                items = me.items,
                idx = items.indexOf(sprite),
                el = sprite.el,
                prevEl;
            if (me.el.dom.childNodes[idx + 2] !== el.dom) { //shift by 2 to account for defs and bg rect
                if (idx > 0) {
                    // Find the first previous sprite which has its DOM element created already
                    do {
                        prevEl = items.getAt(--idx).el;
                    } while (!prevEl && idx > 0);
                }
                el.insertAfter(prevEl || me.bgRect);
            }
            sprite.zIndexDirty = false;
        },

        createItem: function (config) {
            var sprite = new Ext.draw.Sprite(config);
            sprite.surface = this;
            return sprite;
        },

        addGradient: function(gradient) {
            gradient = Ext.draw.Draw.parseGradient(gradient);
            var me = this,
                ln = gradient.stops.length,
                vector = gradient.vector,
                //Safari does not handle linear gradients correctly in quirksmode
                //ref: https://bugs.webkit.org/show_bug.cgi?id=41952
                //ref: EXTJSIV-1472
                usePlain = Ext.isSafari && !Ext.isStrict,
                gradientEl, stop, stopEl, i, gradientsMap;

            gradientsMap = me.gradientsMap || {};

            if (!usePlain) {
                if (gradient.type == "linear") {
                    gradientEl = me.createSvgElement("linearGradient");
                    gradientEl.setAttribute("x1", vector[0]);
                    gradientEl.setAttribute("y1", vector[1]);
                    gradientEl.setAttribute("x2", vector[2]);
                    gradientEl.setAttribute("y2", vector[3]);
                }
                else {
                    gradientEl = me.createSvgElement("radialGradient");
                    gradientEl.setAttribute("cx", gradient.centerX);
                    gradientEl.setAttribute("cy", gradient.centerY);
                    gradientEl.setAttribute("r", gradient.radius);
                    if (Ext.isNumber(gradient.focalX) && Ext.isNumber(gradient.focalY)) {
                        gradientEl.setAttribute("fx", gradient.focalX);
                        gradientEl.setAttribute("fy", gradient.focalY);
                    }
                }
                gradientEl.id = gradient.id;
                me.getDefs().appendChild(gradientEl);
                for (i = 0; i < ln; i++) {
                    stop = gradient.stops[i];
                    stopEl = me.createSvgElement("stop");
                    stopEl.setAttribute("offset", stop.offset + "%");
                    stopEl.setAttribute("stop-color", stop.color);
                    stopEl.setAttribute("stop-opacity",stop.opacity);
                    gradientEl.appendChild(stopEl);
                }
            } else {
                gradientsMap['url(#' + gradient.id + ')'] = gradient.stops[0].color;
            }
            me.gradientsMap = gradientsMap;
        },

        /**
         * Checks if the specified CSS class exists on this element's DOM node.
         * @param {String} className The CSS class to check for
         * @return {Boolean} True if the class exists, else false
         */
        hasCls: function(sprite, className) {
            return className && (' ' + (sprite.el.dom.getAttribute('class') || '') + ' ').indexOf(' ' + className + ' ') != -1;
        },

        addCls: function(sprite, className) {
            var el = sprite.el,
                i,
                len,
                v,
                cls = [],
                curCls =  el.getAttribute('class') || '';
            // Separate case is for speed
            if (!Ext.isArray(className)) {
                if (typeof className == 'string' && !this.hasCls(sprite, className)) {
                    el.set({ 'class': curCls + ' ' + className });
                }
            }
            else {
                for (i = 0, len = className.length; i < len; i++) {
                    v = className[i];
                    if (typeof v == 'string' && (' ' + curCls + ' ').indexOf(' ' + v + ' ') == -1) {
                        cls.push(v);
                    }
                }
                if (cls.length) {
                    el.set({ 'class': ' ' + cls.join(' ') });
                }
            }
        },

        removeCls: function(sprite, className) {
            var me = this,
                el = sprite.el,
                curCls =  el.getAttribute('class') || '',
                i, idx, len, cls, elClasses;
            if (!Ext.isArray(className)){
                className = [className];
            }
            if (curCls) {
                elClasses = curCls.replace(me.trimRe, ' ').split(me.spacesRe);
                for (i = 0, len = className.length; i < len; i++) {
                    cls = className[i];
                    if (typeof cls == 'string') {
                        cls = cls.replace(me.trimRe, '');
                        idx = Ext.Array.indexOf(elClasses, cls);
                        if (idx != -1) {
                            Ext.Array.erase(elClasses, idx, 1);
                        }
                    }
                }
                el.set({ 'class': elClasses.join(' ') });
            }
        },

        destroy: function() {
            var me = this;

            me.callParent();
            if (me.el) {
                me.el.remove();
            }
            if (me._defs) {
                Ext.get(me._defs).destroy();
            }
            if (me.bgRect) {
                Ext.get(me.bgRect).destroy();
            }
            if (me.webkitRect) {
                Ext.get(me.webkitRect).destroy();
            }
            delete me.el;
        }
    });